1. Field of the Invention
This invention relates generally to an indicator, and more particularly, to an indicator carried on a vehicle.
2. Description of the Related Art
Pointer-type indicating devices for indicating measured values such as the vehicle speed and the engine rotation speed are generally carried on a vehicle. These indicating devices each has a character plate provided with indicative characters such as scales, numerals, letters or symbols, a pointer arranged on the character plate, an inner mechanism to drive the pointer according to a measured amount, and a wiring board on which a circuit pattern is provided and to which the inner mechanism is fixed.
The above character plate is formed of a light-transmissive plate made of acrylic resin or polycarbonate resin, and, for example, a printing in dark color is carried out on the face of the light-transmissive plate except the indicative characters. The pointer and the character plate are visible in the day light, and, in the night, the indicative characters are visible by making the indicative characters luminous by passing the light therethrough, which light is from a light source positioned behind the character plate.
There is a demand that the character plate be made of metal in order to give the indicating device a high-grade feeling. However, it would be difficult to print metal on the surface of the light-transmissive plate, and the indicative characters on a metal character plate have not been luminous.
Indicative characters printed on a metal character plate 1 and also a pointer 2 might be lighted up by diodes 3 as shown in FIG. 8. However, in this case, the light is not uniformly irradiated to the whole character plate 1, and high luminance portions A would arise as shown in FIG. 9.